POLYMER ANTIMICROBIAL COMPOSITION

Abstract

This invention relates to an antimicrobial master batch polymer composition comprising: (a) a thermoplastic alkyl polymer, and (b) an antimicrobial; as well as to a polymer composition comprising the antimicrobial master batch polymer composition and a thermoplastic alkyl polymer. This invention also relates to a fabric or moulded product comprising the polymer composition. In addition, the invention relates to a method of making the antimicrobial master batch polymer composition, comprising the steps of: (a) mixing the thermoplastic alkyl polymer powder with the antimicrobial powder, (b) melting the mixture, and (c) cooling the mixture.

Claims

1. An antimicrobial master batch polymer composition comprising: (a) a thermoplastic alkyl polymer; and (b) an antimicrobial.

2. The composition as claimed in claim 1, wherein the polymer is polypropylene, ethylene vinyl acetate, or polyethylene.

3. The composition as claimed in claim 1, wherein the antimicrobial is a chlorophenol compound.

4. The composition as claimed in claim 3, wherein the chlorophenol compound is 4-chloro-3,5-dimethylphenol, 2-chloro-3-methyl-phenol, 2,4-dichloro-3,5-dimethylphenoh or 2,4,6-trichlorophenol.

5. The composition as claimed in claim 1, comprising 5-15 wt % of the antimicrobial.

6. The composition as claimed in claim 5, wherein a remainder of the antimicrobial master batch polymer composition comprises the thermoplastic alkyl polymer and incidental impurities.

7. A method of making a composition as claimed in claim 1, the method comprising: (a) mixing a thermoplastic alkyl polymer powder with an antimicrobial powder to form a mixture; (b) melting the mixture; and (c) cooling the mixture.

8. The method as claimed in claim 7, wherein the weight ratio of thermoplastic alkyl polymer powder to antimicrobial powder in the mixing step is between 17:3 and 19:1.

9. A polymer composition comprising: (a) an antimicrobial master batch polymer composition as claimed in claim 1; and (b) a thermoplastic alkyl polymer.

10. The polymer composition as claimed in claim 9, comprising 1-10 wt % of the antimicrobial master batch polymer composition.

11. A moulded product comprising the polymer composition of claim 9.

12. The moulded product as claimed in claim 11, wherein the product is a bowl, waste bin, curtain, hook, lavatory seat, sharps box, chopping board, container or mat.

13. A method of making a fabric comprising the polymer composition as claimed in claim 9, the method comprising the steps of: (a) forming fibres of the polymer composition; and (b) binding the fibres together.

14. A fabric comprising the polymer composition as claimed in claim 9.

15. A curtain, blind, wheelchair seat cover, pet bed or blanket comprising the fabric as claimed in claim 14.

Description

EXAMPLE

[0038] A polymer composition was formed by mixing polypropylene (PP) powder with 4-chloro-3,5-dimethylphenol (PCMX) powder in a weight ratio of approximately 9:1. The mixture was then passed through a twin-screw extruder at a temperature of around 180° C. The resulting extruded composition was then cooled in a water bath and formed into pellets. These pellets were then mixture with homopolymer polypropylene (HPPL) in the weight amounts described below. The samples were then extruded at 180° C. and formed into sheets.

[0039] Three samples were prepared as follows: [0040] (i) 10 wt % PCMX in PP, 2 wt % in HPPL, [0041] (ii) 10 wt % PCMX in PP, 4 wt % in HPPL, and [0042] (iii) 10 wt % PCMX in PP, 6 wt % in HPPL.

[0043] The samples were in good visible condition.

[0044] 70×45 mm panels of each of the samples were surface inoculated with 0.1 ml culture of the test species as detailed in Table 1 below. The inoculum was spread over the surface using a sterile L shaped spreader and the panels stored at room temperature. At 30 minutes after inoculation the panel surfaces were swabbed and washed with sterile Maximum Recovery Diluent containing preservative neutralisers and the number of survivors determined by serial dilution and plate counting. The plates were then incubated at 34° C. to 36° C. for 48 hours.

TABLE-US-00001 TABLE 1 Initial inoculum level Colony forming Test species units per panel Mixed bacteria: 7.0 × 10.sup.4 Pseudomonas aeruginosa, (ATCC 15442) Escherichia coli, (ATCC 10536) Staphylococcus aureus, (ATCC 6538) Enterococcus hirae, (ATCC 10541) Mixed fungi: 1.1 × 10.sup.4 Candida albicans, (ATCC 10231) Aspergillus brasilliens, (ATCC 16404)

[0045] The test results for the mixed bacteria at 30 minutes after inoculation are shown in Table 2 below.

TABLE-US-00002 TABLE 2 Sample % Reduction at 30 minutes 1 >99.9 2 >99.9 3 >99.9

[0046] The test results for the mixed fungi at 30 minutes after inoculation are shown in Table 3 below.

TABLE-US-00003 TABLE 3 Sample % Reduction at 30 minutes 1 >99.9 2 >99.9 3 >99.9

[0047] These test results indicate that a reduction of greater than 99.9% kill (ie a greater than log 3 reduction) was achieved in a microbial challenge test against a cocktail of bacteria and fungi. Thus, the panels demonstrated a >99.9% reduction in the numbers of bacteria and fungi when the composition was applied to the surface of the plastic panels.